Stress-gradient hypothesis explains annual grass invasion and regime shifts in arid North American sagebrush steppe ecosystems

View article. Cattle herbivory, a novel disturbance and selective force, was a significant component of two overlapping stress gradients most strongly associated with observed shifts in interactions. Facilitation and competition were strongest and most frequent at the highest and lowest stress levels along both gradients, respectively. Contrasting ecological optima among native and non-native beneficiaries led…

Read More

Public perceptions of sagebrush ecosystem management: A longitudinal panel study of residents in the Great Basin, 2006-2010

View dissertation. The study uses data from a mail-back questionnaire sent to residents in 2006 and again in 2010. Overall, 698 respondents comprise the panel of interest. Results suggest landscape scale events such as wildfire, as well as agency management and outreach programs, had little influence on respondents’ perceptions of agencies or management options over…

Read More

The economic impacts of sagebrush steppe wildfires on an eastern Oregon ranch

View thesis. The purpose of this project is to determine the importance of considering specific ecological effects of cheatgrass-associated wildfires on a ranch-level economic model. This study assumes that a representative Oregon 300 cow-calf ranch possesses a Bureau of Land Management (BLM) allotment that exhibits ecological characteristics typical of sagebrush steppe sites that are vulnerable…

Read More

Drivers of plant community dynamics in sagebrush steppe ecosystems: Cattle grazing, heat and water stress

View dissertation. Sagebrush steppe ecosystems are one of the most widespread but endangered ecosystems in North America. A diverse array of human-related stressors has gradually compromised these ecosystems’ resilience to disturbance and invasion by cheatgrass. The role of the foundational shrub Artemisia as a driver of herbaceous community structure and dynamics during this degradation process…

Read More

Resilience to stress and disturbance, and resistance to Bromus tectorum invasion in cold desert shrublands

View article. Cold desert shrublands occur over strong environmental gradients and exhibit significant differences in resilience and resistance. They provide an excellent opportunity to increase our understanding of these concepts. Herein, we examine a series of linked questions about (a) ecosystem attributes that determine resilience and resistance along environmental gradients, (b) effects of disturbances like…

Read More